Correct restoration of the block is impossible if frames may become lost without being noticed in the transmission from the data source to the data sink or if a frame representing the last frame in transmitting a block is not recognized as such and other subsequently received frames are assigned to the same block by the data sink.
The problem of transmitting extensive data blocks which do not fully fit in a frame arises in particular in developing data processing systems based on the CAN standard, for example, of automotive control units. The CAN standard is highly suitable for transmitting small amounts of data within predefined time periods from a sensor to a control unit or from a control unit to an actuator to influence the operating state of an automotive engine or other units of the motor vehicle. However, in developing and optimizing such a system, extensive amounts of data must often be transmitted between the control unit and a host computer of a development environment, enabling the developer to follow the operation of the control unit in an accurate and detailed manner during its dialog with the host computer.
The transmission of such amounts of data via the CAN bus requires considerable overhead and results in a substantial load on the transmission capacity of the CAN bus. When communication of the control unit with the host computer competes for transmission capacity with other communication processes taking place on the bus and required for the control functions performed by the control unit, the transmission capacity may turn out to be insufficient for all functions, and the operability of the unit may be negatively affected.